lightsout

Lights-out is a phrase used to describe turning off all lights in a space. It functions as a general instruction, a policy term, and a name used across several domains, with meanings that range from practical to cultural.

Historically, “lights-out” was associated with blackout policies during wartime. Civil defense authorities imposed curfews and required households to extinguish exterior and interior lighting to make targets harder to spot from the air. These measures varied by country and period but shared the aim of reducing visibility to attackers and preserving resources during emergencies.

In media and entertainment, Lights Out has appeared as titles and concepts. It was the name of a long-running American radio horror program broadcast in the 1930s and 1940s. The term also titles a 2016 American horror film directed by David F. Sandberg, based on a 2013 short film, which centers on a malevolent entity that manifests when lights go out. In games, Lights Out refers to a handheld electronic puzzle game released by Tiger Electronics in 1995, in which pressing a light toggles nearby lights with the goal of turning all lights off.

In technology, lights-out management (LOM) describes remote hardware management for servers and network devices, allowing administration without powering the system fully on. The term is also used in data-center design to evoke operation with minimal on-site intervention.

In sports slang, “lights out” describes a knockout punch or a decisive finish, as in boxing or mixed martial arts.